I was watching a documentary about WW2 era German tech, and learned the the Horten 229 flying wing is actually the first stealth wing aircraft ever created. They aren't sure if the stealth was intended, or a by product of the material components of the plane. but it's a definite influence on the design (s) we have today.

That, and the STG 44 (Sturmgewehr 44) was the very first assault weapon, due to it;s selective fire feature, and it also was the father of the AK 47. Compare it's physical resemblance to the AK-47: